She bought jewelry for her sister. if you wanted to include the idea that charlotte was in paris when she bought the jewelry, which would be the most effective expansion of this sentence? a) when charlotte was in paris, her sister bought jewelry. b) when charlotte was with her sister, she bought paris jewelry. c) when charlotte was in paris, she bought jewelry for her sister. d) she bought jewelry when charlotte was in paris with her sister.

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.